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Thread ID: 70260 2006-06-27 03:41:00 What can give 12V at 11.6amps for cheap? Feelers (10034) PC World Chat
Post ID Timestamp Content User
466582 2006-06-27 03:41:00 I need to power a DC appliance that is 140W, at 12V. I am looking for a simple on/off switch for it, and it needs to be reliable (ie wont spontaenously explode) and cheap.

140W at 12V = 11.66A,

Can anyone suggest a cheap way to power this ~$20? Car battery chargers are more expensive and only give 6A, I was thinking about a PSU, but ones that can supply that many amps at 12V seem to be at least $70. Paralel power packs were suggested - it's a little cluttered for me, and there were suggestions that it would not be very stable. - still dunno about this.

Is there some type of adapter- ie laptop etc, that can supply 11.6 or more amps at 12V on the cheap? :D
Suggestions?
Feelers (10034)
466583 2006-06-27 04:26:00 Presume this is a continuation of the last thread, that tended to go off the rails a bit.
pressf1.pcworld.co.nz

Laptop supplies are not cheap and tend to top out at about 6 amps, plus they are all about 19v.

Look at Jaycar, their MP3110 switchmode unit looks interesting, 150 Watts, 12v but at $130 may be the cheapest (but still unacceptable) option....
godfather (25)
466584 2006-06-27 04:41:00 cheapest....12v battery. all depends on how long you want to run it for.

what sort of applaince is it? some will tolerate fairly crap power so you could get away with a 12v transformer and a bridge diode.
tweak'e (69)
466585 2006-06-27 05:16:00 Presume this is a continuation of the last thread, that tended to go off the rails a bit.
Yeah, not so much that it went off the rails, everyone was really helpful, I was wondering if people might have any ideas that arent based around PSU's.


what sort of applaince is it? some will tolerate fairly crap power so you could get away with a 12v transformer and a bridge diode.
It's for an old car heater fan, it needs to be able to run continously for up to about 4 hours.

This is for a fairly tidy project, I know it could run off a car battery, but I want a functioning independent unit that can be turned on/off with no hassles.
Feelers (10034)
466586 2006-06-27 08:25:00 It's for an old car heater fan, it needs to be able to run continously for up to about 4 hours .




could you get a fan that draws less power??
do you have to use that fan??
robsonde (120)
466587 2006-06-27 08:47:00 Yeah its the only fan that can put out the amount of air I need, (well that I can get for free) . Some serous output - about 200L per second .

I'm considering just biting the bullet and getting a good PSU, although I would rather not :yuck: .
Feelers (10034)
466588 2006-06-27 08:51:00 Yeah its the only fan that can put out the amount of air I need, (well that I can get for free). Some serous output - about 200L per second.

I'm considering just biting the bullet and getting a good PSU, although I would rather not :yuck: .

do you have an electronics wrecker in chch??

we have a few places in wgtn that you can buy old random electronics stuff.
would not be too hard to get a bigass 12V transformer (maybe $20) and then build a clasic bridge rectifier ($5).
robsonde (120)
466589 2006-06-27 12:06:00 Whats the deal with the load ratings on PSU supplies - say I have a 12V 12Amp rated power supply - is this perfectly fine to deal with 12V 12Amp draw all the time - I have been reading about full load as rated at 70%

1.30x12 = ~15Amps

So does that mean I need a 15Amp supply to run a 12Amp apliance? I'll be ****ed off if I do!!! :badpc:
Feelers (10034)
466590 2006-06-27 12:14:00 i sugest go to an auto sparky, borrow his amp meter and hook the fan up to it and a battery. see what it draws at startup and running. tweak'e (69)
466591 2006-06-27 14:47:00 The rating depends on the maker and how honest they are with the true "continuous" capabilities.

As in the other thread, I noted that a commonly available "4 Amp" battery charger is only 4 Amps for a few minutes. Long term it's only 2.2 amps. Things get too hot.

The Jaycar one I suggested above has a peak rating of 35 amps.
godfather (25)
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